North Shore residents flocking to farmers markets this summer should keep in mind that "locally grown" vegetables and fruits aren't always from a field just down the road.

As their popularity grows across the state and country, the organizers of farmers markets are left to define which fresh produce to consider local.

"It's really up to that market to have defined rules and go by them," said Pat Stieren, executive director of the relatively new Illinois Farmers Market Association.

Since 1994, the number of farmers markets in Illinois has more than tripled, from 97 to more than 350, gaining at least 80 new ones in the past five years, said Stieren, a chairman of Illinois Farmers Market Task Force created by the state in 2011. The Chicago area and collar counties now boast about 150 farmers markets, Stieren said.

Usually, "locally grown" produce can be defined as vegetables, fruit, and products such as cheese and eggs that come from within a 150- to 200-mile radius of a farmers market, Stieren said.

Deerfield's Farmers Market bylaws do not include a geographic radius to define what is considered local, but its manager says she knows that customers want produce from nearby.

"We're not interested in having a company from Idaho at our market," said Joan Reed, Deerfield Farmers Market manager. "I don't care how good or what they're selling. That's not what it's about. We're local. We draw our vendors mostly from northern Illinois, Indiana, southwest Michigan and southern Wisconsin. That's our goal — to provide people in this area with locally grown and produced products."

With 30 vendors and growing, the 19-year-old Deerfield market is a relative newcomer compared to the Ravinia Farmers Market in Highland Park, which celebrates its 35th year this season.

Most of Ravinia's 17 or 18 vendors were vetted years ago, said Lydia Davis, who took over the reins of running the market six years ago.

"They're the same produce vendors that have been there all these years, and I've seen some of the farms so I know where they're coming from," Davis said.

While many markets insist that the item for sale is grown by the vendor, Davis said that is not always the case at Ravinia.

"Sometimes they will trade with a neighboring farmer or something, but mostly they grow their own," she said.

The allure of the market is, and has always been, the kind of freshness that just isn't available at metropolitan grocery stores, Davis said.

"It's fresher. It's been picked within days and sometimes the day before," Davis said.

Customers seem to agree. Nicole Belmont, of Deerfield, was at her town's farmers market recently with her mother and dog.

"It's one of the things that makes life worth living," said Rita Slawson, also of Deerfield. "It often tastes so much better than (produce from a) supermarket. At a supermarket you have to shop carefully to make sure it's fresh. Here you know that it's fresh."

Deerfield's and Ravinia's farmers markets fall somewhere in the middle as far as being strict or lenient on vendor restrictions.

Wilmette's is considered a "French Market," meaning food and produce vendors are accompanied by those selling arts, jewelry and other items. Two of the five food vendors are from Illinois, and farmers are not required to grow everything they sell, but all produce must be clearly marked with signs indicating the origin, according to Sebastien Bensidoun, executive vice presidents of Bensidoun USA, which operates the market.

Then there's Oak Park — which some regard as a leader in strictly having only "locally grown" vegetables and fruits on its stands.

It suspended at least one of its vendors, Walt Skibbe, for one week for selling apples he purchased from his neighbors, who had better luck with the weather.

Skibbe, 73, a southwest Michigan farmer who supplies vegetables and fruits to at least seven farmers markets in Illinois, including Northbrook and Deerfield, said he understands the need for strict rules some markets have.

"I know people who develop businesses selling and reselling," said Skibbe, of Eau Claire, Mich., who has grown vegetables and fruits on about 100 acres of his land for about 47 years. "And they don't raise nothin'."

A more regulated farmers market experience may be coming to Illinois, thanks to the Illinois Farmers Market Association, which was created about a year ago in response to the growing trend. The nonprofit aims to educate farmers market managers and farmers about state regulations and best operation practices.

The organization had its first conference in March, and hopes to research the different rules and reach a consensus within the communities in order to eventually come up with a consistent set of statewide administrative regulations for farmers markets, working together with the Illinois Farmers Market Task Force.